Influencer marketing refers to the collaborations between a brand and a content creator who has an engaged audience on social media. This practice is based on a recommendation mechanism: the creator integrates a product or service into their posts, and their audience perceives this message as more credible than a traditional advertisement. Since 2023, the French legal framework has profoundly redefined the rules of the game for advertisers as well as for influencers.
Written contract and legal threshold: what the law mandates since January 2026
Law No. 2023-451 of June 9, 2023, laid the groundwork for regulating commercial influence in France. It applies without a subscriber threshold and covers all platforms, including indirect formats such as promo codes or affiliate links.
Decree No. 2025-1137 of November 28, 2025, which came into effect on January 1, 2026, adds a concrete obligation: a written contract is required for any remuneration of 1,000 euros excluding VAT (in cash or in kind) within a calendar year, for the same advertiser and the same promotional objective. Without this contract, the collaboration may be deemed null and void.
This regulatory evolution transforms the relationship between brands and creators. An article detailing influencers in digital marketing on Business Club highlights how this legal structuring modifies prospecting and negotiation practices on a daily basis.
All sponsored content must also include the mention “Advertising” or “Commercial Collaboration” in a visible manner throughout the duration of the promotion. The absence of this mention constitutes an infringement. Responsibility is shared between the advertiser and the creator, which encourages both parties to formalize each step of the campaign.
Micro-influencers and targeted content strategy
Influencer campaigns no longer rely solely on creators with massive audiences. The distinction between macro-influencers, micro-influencers, and nano-influencers now structures the strategic choices of advertisers.
A micro-influencer, typically active in a specific niche (sports, cooking, parenting, tech), generates a proportionally higher engagement rate than a creator followed by several million people. The smaller audience fosters direct interactions: comments, private messages, shares within close circles.
For a brand, collaborating with several micro-influencers allows reaching complementary audience segments. The logic is not maximum coverage, but the relevance of the message to the targeted community. A creator specialized in hiking who recommends an insulated water bottle produces a recommendation effect comparable to word-of-mouth, amplified by digital reach.
Criteria for selecting a creator for a campaign
- The consistency between the creator’s theme and the promoted product or service, verified through posts from the last six months at a minimum
- The actual engagement rate (ratio of comments and shares relative to the number of subscribers), which matters more than the gross follower volume
- The legal compliance of the creator: systematic mention of commercial collaborations, history without reports to the DGCCRF
- The quality of content production (image, sound, narration), as it directly reflects the image of the associated brand
Measuring the return on investment of an influencer campaign
The management of an influencer campaign relies on precise indicators, and the main difficulty lies in attributing conversions. A click on an affiliate link is traceable. However, the impact of an Instagram story on brand awareness remains more complex to isolate.
Structured advertisers use unique promotional codes per creator to measure direct sales generated. This mechanism allows comparing the performance of each partnership and adjusting budgets accordingly.
Beyond immediate conversion, the value of an influencer campaign is also measured over time. A video content published on YouTube continues to generate views and traffic several months after its release, unlike an ephemeral post on a story. The choice of format determines the lifespan of the message and, by extension, the calculation of return on investment.
Indicators to track according to the objective
- For awareness: impressions, reach, brand mentions, and organic search volume for the brand name after the campaign
- For engagement: comment rate, share rate, average watch time on video formats
- For conversion: number of clicks on tracked links, use of promo codes, customer acquisition cost compared to other channels
Commercial influence and shared responsibility between brands and creators
The French legal framework has introduced a notion that changes the game for marketing departments: the advertiser’s responsibility is engaged on par with that of the creator. A brand can no longer hide behind an influencer’s editorial autonomy to escape sanctions related to an absent or misleading advertising mention.
This shared responsibility compels companies to integrate a legal aspect into every campaign brief. The written contract, made mandatory beyond the legal threshold, must specify transparency obligations, mention formats, and content validation procedures before publication.
Agencies specialized in influencer marketing are adapting their processes: systematic legal review of deliverables, archiving of mention proofs, monitoring of publications after they go live. This professionalization of the sector gradually filters out opaque practices and strengthens the credibility of campaigns with consumers.
Influencer marketing in France now operates within a framework where transparency is no longer optional. Brands that incorporate these legal constraints from the design of their campaigns protect their reputation and obtain stronger partnerships with creators who are themselves concerned about compliance.
